Source Code for Module json_to_relation.output_disposition

  1  ''' 
  2  Created on Sep 14, 2013 
  3   
  4  @author: paepcke 
  5  ''' 
  6  import csv 
  7  import sys 
  8   
  9   
 10 -class OutputDisposition(object): 
 11      ''' 
 12      Specifications for where completed relation rows 
 13      should be deposited, and in which format. Source 
 14      options are files, stdout, and a MySQL table. 
 15       
 16      Also defined here are available output formats, of 
 17      which there are two: CSV, and SQL insert statements.  
 18      ''' 
 19 -    def __init__(self, outputDest): 
 20          ''' 
 21          @param outputDest: os file descriptor for output 
 22          @type outputDest: File 
 23          ''' 
 24          self.outputDest = outputDest 
 25       
 26 -    def __enter__(self): 
 27          return self.outputDest 
 28           
 29 -    def __exit__(self,excType, excValue, excTraceback): 
 30          try: 
 31              self.outputDest.close() 
 32          except: 
 33              # If the conversion itself when fine, then 
 34              # raise this exception from the closing attempt. 
 35              # But if the conversion failed, then have the  
 36              # system re-raise that earlier exception: 
 37              if excValue is None: 
 38                  raise IOError("Could not close the output of the conversion: %s" % sys.exc_info()[0]) 
 39   
 40          # Return False to indicate that if the conversion 
 41          # threw an error, the exception should now be re-raised. 
 42          # If the conversion worked fine, then this return value 
 43          # is ignored. 
 44          return False 
 45   
 46      #--------------------- Available Output Formats 
 47         
 48 -    class OutputFormat(): 
 49          CSV = 0 
 50          SQL_INSERT_STATEMENTS = 1 
 51               
 52  #--------------------- Available Output Destination Options:   
 53           
 54 -class OutputPipe(OutputDisposition): 
 55 -    def __init__(self): 
 56          self.fileHandle = sys.stdout 
 57          # Make file name accessible as property just like  
 58          # Python file objects do: 
 59          self.name = "<stdout>"  # @UnusedVariable 
 60          self.csvWriter = csv.writer(sys.stdout, dialect='excel', delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL) 
 61           
 62 -    def close(self): 
 63          pass # don't close stdout 
 64       
 65 -    def __str__(self): 
 66          return "<OutputPipe:<stdout>" 
 67   
 68 -    def writerow(self, colElementArray): 
 69          self.csvWriter.writerow(colElementArray) 
 70   
 71 -class OutputFile(OutputDisposition): 
 72 -    def __init__(self, fileName, options='ab'): 
 73          # Make file name accessible as property just like  
 74          # Python file objects do: 
 75          self.name = fileName  # @UnusedVariable 
 76          # Open the output file as 'append' and 'binary' 
 77          # The latter is needed for Windows. 
 78          self.fileHandle = open(fileName, options) 
 79          self.csvWriter = csv.writer(self.fileHandle, dialect='excel', delimiter=',', quotechar='"', quoting=csv.QUOTE_MINIMAL) 
 80           
 81 -    def close(self): 
 82          self.fileHandle.close() 
 83   
 84 -    def __str__(self): 
 85          return "<OutputFile:%s>" % self.name 
 86   
 87 -    def writerow(self, colElementArray): 
 88          self.csvWriter.writerow(colElementArray) 
 89   
 90 -class OutputMySQLTable(OutputDisposition): 
 91 -    def __init__(self, server, pwd, dbName, tbleName): 
 92          raise NotImplementedError("MySQL connector not yet implemented") 
 93          self.name = "<MySQL:%s:%s:%s>" % (server,dbName,tbleName) 
 94          self.server = server 
 95          self.pwd = pwd 
 96          self.dbName = dbName 
 97          self.tbleName = tbleName 
 98          self.fileHandle = self.connect() 
 99           
100 -    def connect(self): 
101          raise NotImplementedError("MySQL connector not yet implemented") 
102       
103 -    def close(self): 
104          raise NotImplementedError("MySQL connector not yet implemented") 
105   
106 -    def __str__(self): 
107          return "<OutputMySQLTable--%s>" % self.name 
108   
109 -    def writerow(self, fd, colElementArray): 
110          raise NotImplementedError("MySQL connector not yet implemented") 
111